Presence of a Long‐Term Lithospheric Thermal Anomaly: Evidence from Apatite Fission‐Track Analysis in Northern New England

Apatite fission‐track (AFT) ages from 56 samples of Paleozoic and Mesozoic crystalline rocks in New Hampshire, northeastern Vermont, and western Maine range from 70 to 140 Ma and reflect widespread Early to Late Cretaceous cooling. The regional AFT age distributions determined in this study suggest...

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Bibliographic Details
Published in:The Journal of geology 2009-11, Vol.117 (6), p.627-641
Main Authors: Roden‐Tice, Mary K., West Jr, David P., Potter, Jaime K., Raymond, Sarah M., Winch, Jenny L.
Format: Article
Language:English
Subjects:
Annealing
Apatites
Cooling
Geology
Meteors
Mountains
Petrology
Plutons
Rocks
S waves
Stratigraphy
Studies
Wave velocity
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Summary:Apatite fission‐track (AFT) ages from 56 samples of Paleozoic and Mesozoic crystalline rocks in New Hampshire, northeastern Vermont, and western Maine range from 70 to 140 Ma and reflect widespread Early to Late Cretaceous cooling. The regional AFT age distributions determined in this study suggest that reactivation of preexisting orogen‐parallel faults and the presence of a long‐lived thermal anomaly in the lithospheric mantle controlled the late unroofing history of this part of the northern Appalachians. A northeast‐trending zone of young, dominantly Late Cretaceous AFT ages (70–118 Ma) extends from southwestern New Hampshire through the central White Mountain region and continues into northern New Hampshire, northeastern Vermont, and western Maine, providing evidence for regional NW‐SE extension and cooling at this time. Significantly older AFT ages (125–140 Ma) in the region bounded by the Bill Little, Ammonoosuc, and Northey Hill faults in northwestern New Hampshire suggest a normal‐sense reactivation associated with NW‐SE extension at
ISSN:0022-1376
1537-5269
DOI:10.1086/605995